In recent years, electronic control units (ECUs) mounted to a vehicle have advanced functions, and programs executed in the ECUs are more complicated accordingly.
Moreover, multiple ECUs are mounted to a vehicle and are connected with each other via a network such as a controller area network (CAN). The multiple ECUs perform processing while exchanging information through the network.
Japanese Patent Application Laid-Open Publication No. 2014-86812 describes a CAN system that aims to enhance fault tolerance by transmitting a retransmission request frame in the case where the first node in the CAN system fails to receive a frame and is in an error passive state, storing by the second node a frame transmitted to a CAN bus, and retransmitting the frame for which retransmission is requested to the first node.
Japanese Patent Application Laid-Open Publication No. 2011-103577 describes a communication system that aims to prevent erroneous operation on the reception side of a frame by having such a configuration that a CAN controller measures transmission latency from the input of a frame to the start of transmission to the CAN bus and transmits the frame together with information related to the transmission latency, while deciding processing to be executed in accordance with the transmission latency by the CAN controller which received the frame.